Comprehensive Evaluation Report

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Revision Topic 1: Ecosystem Diversity Current Conditions and Trends Using the National Hierarchical Framework of Ecological Units, an analysis of the distribution of current vegetation types across the landscapes surrounding the Grasslands was completed using the Section and Subsection units. Collectively, the four sections within which the Grasslands are located total over 65 million acres. The Grasslands make up less than 2% of these total acres. The majority of the land within these sections is privately-owned agriculture or crop land. Irrigated agriculture areas used for cropland are used mainly to farm soybeans, corn, or alfalfa. The main crops grown through dry-farming are winter wheat, beans, small grains, or sorghum. Much of the remaining vegetation is either shortgrass or mixed grass prairie; however, as the majority of the land ownership is private, most of these acres are used as rangeland for grazing cattle. The Grasslands are part of the larger Great Plains grassland ecosystem (Figure 4); however, each Grassland has unique characteristics. Analysis of these unique ecosystems was conducted using Potential Natural Vegetation Types (PNVTs) and existing mid- Figure 4: Great Plains Region scale vegetation types found on the Grasslands. PNVTs are coarse-scale groupings of ecosystem types that share similar geography, vegetation, and historical disturbances such as fire, drought, and native herbivory. The PNVTs used for this analysis were summarized from the Terrestrial Ecological Unit Inventory (TEUI) data for the Grasslands. There are seven PNVTs found on the Grasslands. A comparison between PNVTs and existing vegetation was used to show the departure from reference conditions. 2 Existing dominant vegetation and PNVT maps can be found in Appendix A. Vegetation 3 There are seven distinct PNVTs (ecosystem types) found across the Grasslands: Mixed Grass Prairie, Shinnery Oak, Mixed Hardwood Riparian, Shortgrass Prairie, Pinyon-Juniper, Cottonwood Willow Riparian, and Sand Sagebrush. A broad-scale analysis of the departure of current conditions from reference condition for each PNVT was done to set the context for the contributions the Grasslands make to ecological sustainability. Reference conditions, as described, in this document are referencing conditions of ecosystems in terms of vegetation composition and structure only. Reference conditions do not describe the extent or distribution of the PNVT across the landscape because these ecosystems would have historically covered millions of contiguous acres across the southern Great Plains. Due to settlement, landownership patterns across the landscape have become highly fragmented. As a result, four out of the 2 Mid-scale vegetation type description is structural, not compositional. Description of existing species composition was inferred by relating remotely sensed data (mid-scale) to ground-based data (TEUI). Comparison of existing vegetation to reference condition is therefore limited to plant community structure (not species composition). 3 USDA 20011a p. 15-30 and 65-75 8
seven PNVTs found on the Grasslands (Shinnery Oak, Pinyon-Juniper, Mixed Hardwood Riparian, and Sand sagebrush) have greater representation on the Grasslands than they do in the surrounding landscape. When looking to identify resource management opportunities and constraints, two key factors should be considered: the current status and trend of an ecosystem and the effects of current management activities on that status and trend. Using these considerations and recognizing the importance of other ecosystem characteristics (i.e., soil, water, air and habitat) each PNVT and habitat feature found on the Grasslands was reviewed to identify general management opportunities and constraints for the Grasslands. Historically, natural disturbance was a regular component of all of the PNVTs found on the Grasslands. These disturbances, including wildfire, grazing, climatic events, and invasive species, had notable effects on the Grasslands vegetation (including composition and structure). In addition to these events, hardwood riparian areas were periodically affected by flooding. Though their frequency and intensity have shifted as a result of settlement and management, these historical natural disturbances continue to influence the composition and structure of the Grassland PNVTs. In addition to these historical natural disturbances, invasive species and motorized and off-road travel are now recognized as having disturbance-like effects on the Grasslands vegetation. Both have the potential to significantly modify ecological systems and processes. Mixed Grass Prairie Condition: Mixed grass prairie covers approximately 11,300 acres or 35% of the Black Kettle and McClellan Creek National Grasslands. The mixed grass prairie PNVT is characterized by mixed grass to tall grass prairie found on moderate to gentle slopes and is dominated by one or some of the following species: big bluestem; little bluestem; western wheatgrass; sideoats grama and blue grama. This PNVT may also include areas that are dominated by low structure grasses and forbs. In the early stage, 1-3 years post-fire, there are more forbs and diversity of species before little bluestem regains dominance. After approximately three years, the grasses become the dominant species. Perennial grasses on the red-shale soils are primarily blue grama, hairy grama, little bluestem, and purple three awns. About 10% of the areas are covered in forbs and 10% in woody species. Trends: Prescribed fire and livestock grazing would produce plant communities with increased forb composition within the mixed-grass prairie, and maintain current structure conditions. Departure from Reference: The mixed grass prairie that occurs on soils that are a loamy, red-shale type and are currently near reference condition. Contribution to Sustainability and Management Opportunities and Constraints: Currently, The Subsections, Canadian-Cimarron Breaks and Red Prairie, have disproportionate total percentages of mixed grass prairie compared to the percentage of mixed grass prairie on the Grasslands within those Subsections. The McClellan Creek boundary overlaps the Canadian-Cimarron Breaks Subsection and the disproportionately larger percentage of mixed grass on McClellan Creek is due to the small size of this unit and the lack of PNVT diversity considering the topography and overall landscape constraints. The disproportionately small percentage of mixed grass prairie within the Red Prairie Subsection and Black Kettle boundary overlap is largely due to the soil types in this area of the Grasslands that are more conducive to other PNV types. While it may appear that management of the mixed grass prairie on the Grasslands is not a priority due to its overrepresentation on private land, much of all mixed grass prairie off of the Grasslands is highly departed from its reference condition due to historical agricultural practices and land use. This makes the native mixed grass prairie located on the Black Kettle and McClellan Creek National Grasslands important, as it has a high contribution to the overall ecological sustainability. 9
Page 1 and 2: United States Department of Agricul
Page 3 and 4: Executive Summary This Comprehensiv
Page 5 and 6: three percent of the land with the
Page 7 and 8: Historical Context Beginning about
Page 9: ural region would be substantially
Page 13 and 14: Departure from Reference: The shinn
Page 15 and 16: making this an important ecosystem.
Page 17 and 18: conditions relationship to referenc
Page 19 and 20: # Common Name Ranger District Habit
Page 21 and 22: determined not to be at risk. None
Page 23 and 24: Hiking and Camping 13 Based on surv
Page 25 and 26: eplace facilities at the end of the
Page 27 and 28: o The revised plan should acknowled
Page 29 and 30: Livestock and Range Management 21 O
Page 31 and 32: tree removal practices are designed
Page 33 and 34: vital role in supporting social and
Page 35: USDA Forest Service. 2011b. Socio-E

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